Comment by Tiberium

Godot packs the whole engine runtime when packing the game no matter the platform, but in this case it's also probably because the internet connection on the server is slow - https://lfgslots.com/classicvideopoker/index.wasm (26MB, main engine runtime) took me 22s to load, and https://lfgslots.com/classicvideopoker/index.pck (16MB, game resources) 34s.